Calibrating Humi-Care digital hygrometer

Hi guys, I need some help calibrating a specific model of hygrometer I recently bought from this website. I don't know if it ever came with documentation, but in my excitement to get to the good stuff (the sticks, not the equipment!) I may have thrown it out with the packaging.

Regardless, the thing is sitting in a ziploc bag undergoing the "salt test" for 75% humidity as I type. My question is more in line with this specific model rather than the process. I got the Humi-Care digital hygrometer to replace an older analog one.

I assume to calibrate it I merely have to turn the dial with the drop on it? Part of the problem is I see no change when I turn the dial to know if it's working. Further complicating things is the fact that it is so immediate in its readings it starts dropping continuously as soon as it comes out of the bag, complicating any potential adjustment. Now I'm currently stationed in Afghanistan, so it has a long way to drop! I worry that if I wait until it hits the bottom, somewhere in the 30s I think, and I try to adjust it there that it won't be as accurate as adjusting it closer to the 75% end of the scale.

Does anyone have any tips or experience in calibrating this particular model?

Ken

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if you can see through the bag that it is calibrating in then you know how much it is off. my hygrometer is low by 4. i cant calibrate it but since i know its off by that much i will always add that in when i check the humidity. 9 times out of 10 my RH reads 61%rH ... add 4 back in... 65%rH. Perfect. or you can salt test it, remember how far off it is. set it out, let it stop falling, then adjust accordingly.

I've had the same problem. I salt test it to 74%, hit the set button, it cycles through and reads 71%, what gives?

You're 100% positive that you're doing the salt test correctly, right? An easier way to calibrate the hygro is to remember how far off it is when you salt-test it. In your case, it's -1%. Then, after you take it out of the bag, leave it out in the open air for a few hours so it can normalize with the ambient room Rh. ONLY after it's stabilized, turn the knob one click and then push the reset button. This will prevent the rapidly changing ambient Rh from **** with the calibration.

Hey Everybody . . . . . I've had several of these hygrometers for at least 5 years. They pretty reliable as I also have another hygrometer in each humidor. The batteries finally died and when I put in new ones the humidity reading changed. I cound not remember exactly how to recalibrate . . . . what the red button was for? Anyway. Thanks for the help.

Welcome to the forum, If I remember correctly, after you have checked the RH reading (salt test or Boveda calibration kit) and made any adjustments the red button resets the hygrometer and locks in the new setting. I recently changed a bunch of batteries and only had to make adjustments on 2, still it's probably best to retest and make sure.